// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/threading/thread_id_name_manager.h"

#include <stdlib.h>
#include <string.h>

#include "base/logging.h"
#include "base/memory/singleton.h"
#include "base/strings/string_util.h"
#include "base/trace_event/heap_profiler_allocation_context_tracker.h"

namespace base {
namespace {

    static const char kDefaultName[] = "";
    static std::string* g_default_name;

}

ThreadIdNameManager::ThreadIdNameManager()
    : main_process_name_(NULL)
    , main_process_id_(kInvalidThreadId)
{
    g_default_name = new std::string(kDefaultName);

    AutoLock locked(lock_);
    name_to_interned_name_[kDefaultName] = g_default_name;
}

ThreadIdNameManager::~ThreadIdNameManager()
{
}

ThreadIdNameManager* ThreadIdNameManager::GetInstance()
{
    return Singleton<ThreadIdNameManager,
        LeakySingletonTraits<ThreadIdNameManager>>::get();
}

const char* ThreadIdNameManager::GetDefaultInternedString()
{
    return g_default_name->c_str();
}

void ThreadIdNameManager::RegisterThread(PlatformThreadHandle::Handle handle,
    PlatformThreadId id)
{
    AutoLock locked(lock_);
    thread_id_to_handle_[id] = handle;
    thread_handle_to_interned_name_[handle] = name_to_interned_name_[kDefaultName];
}

void ThreadIdNameManager::SetName(PlatformThreadId id,
    const std::string& name)
{
    std::string* leaked_str = NULL;
    {
        AutoLock locked(lock_);
        NameToInternedNameMap::iterator iter = name_to_interned_name_.find(name);
        if (iter != name_to_interned_name_.end()) {
            leaked_str = iter->second;
        } else {
            leaked_str = new std::string(name);
            name_to_interned_name_[name] = leaked_str;
        }

        ThreadIdToHandleMap::iterator id_to_handle_iter = thread_id_to_handle_.find(id);

        // The main thread of a process will not be created as a Thread object which
        // means there is no PlatformThreadHandler registered.
        if (id_to_handle_iter == thread_id_to_handle_.end()) {
            main_process_name_ = leaked_str;
            main_process_id_ = id;
            return;
        }
        thread_handle_to_interned_name_[id_to_handle_iter->second] = leaked_str;
    }

    // Add the leaked thread name to heap profiler context tracker. The name added
    // is valid for the lifetime of the process. AllocationContextTracker cannot
    // call GetName(which holds a lock) during the first allocation because it can
    // cause a deadlock when the first allocation happens in the
    // ThreadIdNameManager itself when holding the lock.
    trace_event::AllocationContextTracker::SetCurrentThreadName(
        leaked_str->c_str());
}

const char* ThreadIdNameManager::GetName(PlatformThreadId id)
{
    AutoLock locked(lock_);

    if (id == main_process_id_)
        return main_process_name_->c_str();

    ThreadIdToHandleMap::iterator id_to_handle_iter = thread_id_to_handle_.find(id);
    if (id_to_handle_iter == thread_id_to_handle_.end())
        return name_to_interned_name_[kDefaultName]->c_str();

    ThreadHandleToInternedNameMap::iterator handle_to_name_iter = thread_handle_to_interned_name_.find(id_to_handle_iter->second);
    return handle_to_name_iter->second->c_str();
}

void ThreadIdNameManager::RemoveName(PlatformThreadHandle::Handle handle,
    PlatformThreadId id)
{
    AutoLock locked(lock_);
    ThreadHandleToInternedNameMap::iterator handle_to_name_iter = thread_handle_to_interned_name_.find(handle);

    DCHECK(handle_to_name_iter != thread_handle_to_interned_name_.end());
    thread_handle_to_interned_name_.erase(handle_to_name_iter);

    ThreadIdToHandleMap::iterator id_to_handle_iter = thread_id_to_handle_.find(id);
    DCHECK((id_to_handle_iter != thread_id_to_handle_.end()));
    // The given |id| may have been re-used by the system. Make sure the
    // mapping points to the provided |handle| before removal.
    if (id_to_handle_iter->second != handle)
        return;

    thread_id_to_handle_.erase(id_to_handle_iter);
}

} // namespace base
